As the practice of receptive anal intercourse is not limited to men who have sex with men (MSM), and there is clear evidence of both receptive vaginal and anal intercourse in the same sexual act, there is a strong rationale for the development of a microbicide formulation that is suitable for both rectal and vaginal application. A dual compartment microbicide formulation will reduce the complexity of maintaining separate dosage forms for women who engage in both anal and vaginal sex. With the promising development of the IQP-0528/TFV combination vaginal gel, a novel dual vaginal and rectal gel (DuoGel) will be developed in Project 1 from the preexisting gel formulation. In addition, to directly address potential issues of user acceptability and physiological differences between the vagina and rectum in a dual chamber microbicide product, a